466 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



Water Sample from same place. 



Mean No. of sewage bacteria = 485 per c.c. 



Roosebecl 



i. Mussels 23 Oct., 1913. 







Plate 1, No. 



of red colonies, ; No. of white colonies, 



This is in 



„ 2 



„ o 



o 



l/50th 



„ 3 





o 



o 



mussel. 



» 1 





1 



o 





„ 2 





o 



o 



This is in 



„ 3 





o 



o 



■ l/25th 



„ 4 





, o 



o 



mussel. 



„ 5 





o 



oj 





„ 1 





2 



o 



This is in 



„ 2 





1 



o 



l/10th 



„ 3 





, o 



o 



mussel. 



In all these analyses typical colonies, isolated by the 

 neutral-red agar medium employed, have been grown in 

 pure subculture and examined in detail. Several interest- 

 ing questions have arisen in connection with the biological 

 characters of the organisms isolated, such as that of a 

 possible change in the reactions of bacteria having their 

 normal habitat in the intestine of a warm-blooded animal 

 and then passing into the alimentary canal of a marine 

 mollusc. Such a possible change of character is being 

 investigated, and will form the subject of a further report, 

 when the biology of the micro-organisms isolated in this 

 investigation will also be discussed. 



Explanation of the Plates. 



Plate I. Port Madoc and neighbouring channels. 

 ,, II. Estuary of the Dovey— Cardigan Bay. 

 ,, III. Estuary of the Mawddach — Cardigan Bay. 

 ,, IV. Eibble Estuary from the Sea to Preston. 

 ,, Y. 1. Organisms present in l/50th mussel from the 



Eibble Estuary. 2. Organisms present in 



1/5 Oth mussel from the Dovey Estuary. 



3. Organisms present in 1 c.c. of water 



from the Eibble Estuarv. 



